B10 cells are a sub-class of regulatory B cells (Breg cell) that are involved in inhibiting immune responses in both humans and mice.[1][2][3] B10 cells are named for their ability to produce inhibitory interleukin: Interleukin-10 (IL-10).[4][5] One of their unique abilities is that they suppress the innate and adaptive immune signals, making them important for regulating the inflammatory response. Like the B cell, the B10 cell requires antigen specific binding to the surface of CD5 receptor to elicit a response from the T cell. Once an antigen binds to the CD19 receptor, immediate downregulation in B-cell receptor (BCR) signal expression occurs and mediates the release of IL-10 cytokines.[3] In mice and humans, B10 cells are distinguishable in their expression of measurable IL-10 due to the lack of unique cell surface markers expressed by regulatory B cells.[1][3] However, IL-10 competence is not limited to any one subset of B cells.[3] B10 cells do not possess unique phenotypic markers or transcription factors for further identification.[6] B10 cells predominantly localize in the spleen, though they are also found in the blood, lymph nodes, Peyer's patches, intestinal tissues, central nervous system, and peritoneal cavity.[1] B10 cells proliferate during inflammatory and disease responses.[3]
History
editSauropsida divergence was coincident with the emergence of B10.[7] B10 markers have been expressed since this divergence event, including CD19, CD1d, IL-21, and CD5 markers.[7] CD24, a human B10 marker, is exclusive to higher vertebrates and is absent in Vombatus and the organisms that diverged prior.[7]
The B10 cell was first characterized in 2008, as a different subset of B cells in mice. By inducing hypersensitive T cells, the immune response of the mice was over-expressed.[3] When compared to the wild type or normal expression of antigen receptors, the B cells bound to CD19 molecules actually decreased inflammation. The in vivo model demonstrated that a new characterization of B cell was producing IL-10 which was later defined as the B10 effector (B10eff) cells.
Development and differentiation
editB10 cells are presumed to originate from B10 progenitor (B10pro) cells, which can mature into B10eff cells with lipopolysaccharide (LPS) stimulation or CD40 litigation.[1][8] In mice, B10eff cells (derived from B10 cells) actively secrete IL-10, whereas competency for IL-10 expression in B10pro cells must be induced by ex vivo stimulation.[1] BCR signals are fundamental to the development of B10pro cells which can develop into B10eff cells in the presence of CD40 signals, LPS, or IL-21.[1] Some B10eff cells further develop into Ab-secreting plasma cells.[1] B10 cell development is antigen (Ag)-regulated through BCR signaling pathways which select for Ag-specific B10 cells and stimulate IL-10 competency.[1][3] In vitro identification of IL-10-competent cells can occur by stimulation of B cells using PMA and ionomycin.[3]
Within the spleen of C57B1/6 mice, B10 cells comprise 1-3% (and B10+B10pro cells comprise 3-8%) of B cells.[3][9] B10pro cell numbers are comparatively more consistent than B10 cells during immune responses.[3] The general phenotype of B10 splenic cells is IgMhi IgDlo CD19hi MHC-IIhi CD21int/hi CD23lo CD24hi CD43+/- CD93-.[3] Characteristics of this phenotype are similar to immature transitional B cells, marginal zone B cells, and peritoneal B1 cells.[3] Peritoneal B10 cells share a similar phenotype but express lower levels of CD1d.[3] Mouse B10 cells in the spleen are enriched in the B cell subset CD1dhiCD5+, whereas human B10 and B10pro peripheral blood cells are enriched in the B cell subset CD24hiCD27+.[6]
Function
editBCR-antigen interactions and BCR signaling facilitate antigen specificity and reactivity of B10 cells.[3] B10 cell germline BCRs interact with and present antigens to respective CD4+ T cells.[3] These cognate interactions are dependent on MHC-II and CD40, and encourage IL-10 production and enable B10 cells to suppress macrophage function.[3][6] While cognate CD4+ T cell and B10 cell interactions are critical for B10eff cell functioning, T cells are not.[6] The anti-inflammatory cytokine IL-10 suppresses innate and adaptive immune signals by prohibiting T cell activation, in addition to IFN-γ and Th17 cytokine responses.[1][3] Another cytokine, IL-21, regulates B10eff cell functionality in its integral role to the expansion of B10 cells and secretion of B10eff cells in autoimmune responses.[1]
By a similar regulatory mechanism, the development of B10pro cells is inhibited by TGF-β and IFN-γ.[1] Through their inhibitory effects, B10 cells interfere with antigen-presenting abilities, the production of cytokines, and the activation of dendritic cells.[1] In addition, their secretion of IL-10 can interfere with the phagocytosis, the activation of macrophages, and the production of cytokines and nitric oxide (NO). [1] IL-10 production is regulated, as is the functioning of local macrophages and Ag-specific T cells.[1] By this specificity, IL-10 is delivered to sites of inflammatory and immune response.[3] CpG oligonucleotides promote IL-10 production in competent B10 cells.[1][3] Similarly, innate signals such as IL-1β, IL-6, IL-33, IL-35, TLR signals, infection, and apoptotic cells may proliferate B10 and B10eff cells.[1][3] In the peripheral blood of patients with autoimmune diseases, B10 cell numbers are typically expanded.[6]
Therapeutic potential
editB10 cells have been studied in mouse models on account of their therapeutic relevance to autoimmune disease.[3] In mouse models, the introduction of additional B10 cells during disease onset can mitigate and accelerate disease-related symptoms and progression.[3] Purified B10 cells of subsets including CD1dhiCD5+ B cells and peritoneal cavity B cells demonstrate suppressive effects for Ag-specific responses especially.[1][10] Therapeutic potential for B10 cells was first revealed by the Londei laboratory through induced B cell-expression of IL-10, then later by studies using B10eff cell expansion, both instances of which demonstrated therapeutic effects in the context of disease initiation and progression.[1] Autoimmune disease and cancer treatments are possible through either the preferential expansion or depletion of B10 cells.[6][11]
Disease progression in patients with autoimmune diseases such as lupus or rheumatoid arthritis can commence with insufficient B10 cell numbers.[1] Moreover, B10 cell expansion in the absence of autoimmune-related production of inflammatory cytokine factors provides potential for immune response, allergy, and transplant rejection treatment.[1] Agonistic CD40 antibodies enable in vivo B10 cell expansion, though unwanted responses from additional immune cells may transpire.[6] Ex vivo B10 cell expansion is also possible, though this method is limited in expansion methods, magnitude, and time.[6] Induced B10 cell expansion in esophageal squamous cell carcinoma (ESCC) patients and subsequent elevated IL-10 production support the role of B10 cells in regulating disease progression, specifically through restrained inflammatory responses.[3][4] As such, in adequate quantities, B10 cells can both regulate and treat diseases.[6]
B10 cells are prevalent in the human solid tumor and peritumoral tissues of several cancers, including lung, hepatocellular carcinoma, and breast cancers.[12] Their ability to promote cancer growth is attributed to immunosuppression mechanisms through innate and adaptive immune responses.[12] B10 cell depletion can amplify cellular, innate, and humoral immune system responses and might aid in immune responses to cancer therapy, infectious diseases, and vaccines.[1] The depletion of B10 cells enables a more rapid immune response and can improve pathogen clearance.[3] Further, inhibited B10 cell functioning can improve anticancer responses.[3] The preferential depletion of B10 cells provides therapeutic potential for enhanced anticancer responses due to the intrinsic ability of B10 cells to impede antitumor immune responses.[3]
References
edit- ^ a b c d e f g h i j k l m n o p q r s t u Tedder TF (February 2015). "B10 cells: a functionally defined regulatory B cell subset". Journal of Immunology. 194 (4): 1395–1401. doi:10.4049/jimmunol.1401329. PMID 25663677. S2CID 207430556.
- ^ Candando KM, Lykken JM, Tedder TF (May 2014). "B10 cell regulation of health and disease". Immunological Reviews. 259 (1): 259–272. doi:10.1111/imr.12176. PMC 4049540. PMID 24712471.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Lykken JM, Candando KM, Tedder TF (October 2015). "Regulatory B10 cell development and function". International Immunology. 27 (10): 471–477. doi:10.1093/intimm/dxv046. PMC 4817073. PMID 26254185.
- ^ a b Mao Y, Wang Y, Dong L, Zhang Q, Wang C, Zhang Y, et al. (September 2019). "Circulating exosomes from esophageal squamous cell carcinoma mediate the generation of B10 and PD-1high Breg cells". Cancer Science. 110 (9): 2700–2710. doi:10.1111/cas.14122. PMC 6726703. PMID 31276257.
- ^ Liu J, Chen X, Hao S, Zhao H, Pang L, Wang L, et al. (October 2019). "Human chorionic gonadotropin and IL-35 contribute to the maintenance of peripheral immune tolerance during pregnancy through mediating the generation of IL-10+ or IL-35+ Breg cells". Experimental Cell Research. 383 (2): 111513. doi:10.1016/j.yexcr.2019.111513. PMID 31362000. S2CID 198998443.
- ^ a b c d e f g h i Kalampokis I, Yoshizaki A, Tedder TF (2013-02-11). "IL-10-producing regulatory B cells (B10 cells) in autoimmune disease". Arthritis Research & Therapy. 15 (Suppl 1): S1. doi:10.1186/ar3907. PMC 3624502. PMID 23566714.
- ^ a b c Mickael ME, Bieńkowska I, Sacharczuk M (May 2022). "An Update on the Evolutionary History of Bregs". Genes. 13 (5): 890. doi:10.3390/genes13050890. PMC 9141580. PMID 35627275.
- ^ Poe JC, Smith SH, Haas KM, Yanaba K, Tsubata T, Matsushita T, Tedder TF (2011-07-25). "Amplified B lymphocyte CD40 signaling drives regulatory B10 cell expansion in mice". PLOS ONE. 6 (7): e22464. Bibcode:2011PLoSO...622464P. doi:10.1371/journal.pone.0022464. PMC 3143148. PMID 21799861.
- ^ Iwata Y, Matsushita T, Horikawa M, Dilillo DJ, Yanaba K, Venturi GM, et al. (January 2011). "Characterization of a rare IL-10-competent B-cell subset in humans that parallels mouse regulatory B10 cells". Blood. 117 (2): 530–541. doi:10.1182/blood-2010-07-294249. PMC 3031478. PMID 20962324.
- ^ Maseda D, Smith SH, DiLillo DJ, Bryant JM, Candando KM, Weaver CT, Tedder TF (February 2012). "Regulatory B10 cells differentiate into antibody-secreting cells after transient IL-10 production in vivo". Journal of Immunology. 188 (3): 1036–1048. doi:10.4049/jimmunol.1102500. PMC 3262922. PMID 22198952.
- ^ Horikawa M, Minard-Colin V, Matsushita T, Tedder TF (November 2011). "Regulatory B cell production of IL-10 inhibits lymphoma depletion during CD20 immunotherapy in mice". The Journal of Clinical Investigation. 121 (11): 4268–4280. doi:10.1172/JCI59266. PMC 3204847. PMID 22019587.
- ^ a b Wu H, Su Z, Barnie PA (January 2020). "The role of B regulatory (B10) cells in inflammatory disorders and their potential as therapeutic targets". International Immunopharmacology. 78: 106111. doi:10.1016/j.intimp.2019.106111. PMID 31881524. S2CID 209500182.